Adjustable back-rest

ABSTRACT

A novel form of adjustable back-rest is described which is particularly suited for attachment to a stretcher, cot or bed. The back-rest has a U-shaped tubular frame with a pair of side limbs joined by an upper cross bar. A yoke member in the form of a pair of parallel spaced ears with a slot between them is mounted at the lower end of each side limb and these ears are pivotally connected to a clamp member connecting the back-rest to a stretcher, cot or bed. Each clamp member has a projection extending into the slot and this projection has an arcuate face parallel to the pivot axis, this arcuate face having a series of spaced, radially extending holes. A locking pin is mounted in each yoke member and the pin is spring-biased into engagement with one of the radial holes. The pins in each yoke are connected together by an elongated flexible member, e.g., a wire cable, which extends up through and across between the side limbs with a portion of the flexible member between the side limbs being exposed as a loop. By grasping and pulling on this loop the pins are released from the holes in both sides of the back-rest so that it can be easily adjusted by a simple pull on the loop in the upper region of the back-rest.

United States Patent [1 1 Bradford 1 ADJUSTABLE BACK-REST [76] Inventor: John Guythar Bradford, 47

Mansfield Dr., Ancaster, Ontario, Canada [22] Filed: Sept. 19, 1973 [211 App]. No.: 398,595

Primary Examiner-Paul R. Gilliam Assistant Examiner-Andrew M. Calvert Attorney, Agent, or Firm-Christen & Sabol [451 Feb. 18,1975

[57] ABSTRACT A novel form of adjustable back-rest is described which is particularly suited for attachment to a stretcher, cot or bed. The back-rest has a U-shaped tubular frame with a pair of side limbs joined by an upper cross bar. A yoke member in the form of a pair of parallel spaced ears with a slot between them is mounted at the lower end of each side limb and these cars are pivotally connected to a clamp member connecting the back-rest to a stretcher, cot or bed. Each clamp member has a projection extending into the slot and this projection has an arcuate face parallel to the pivot axis, this arcuate face having a series of spaced, radially extending holes. A locking pin is mounted in each yoke member and the pin is spring-biased into 8 Claims, 6 Drawing Figures PATENTEB FEB 1 8 I975 SHEET F! HF 2 FIG.4

FIG.6

ADJUSTABLE BACK-REST BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to an adjustable back-rest, particularly for use in association with a stretcher, cot or bed.

2. Description of the Prior Art Adjustable back-rests have been known for many years and have been used in automobiles, patio chairs, hospital beds, etc. The mechanisms for these adjustable back-rests have tended to be either heavy and complex such as are used in automobiles and hospital beds or very cheap and clumsy such as is typically found in patio chairs. U.S. Pat. No. 2,515,261 illustrates a hinged back member having an arrangement for adjusting the angleof the back with this adjustment means being positioned upwardly on the rear surface of the seat back to enable manual adjustment. However, the mechanism shown in this patent is much too heavy and complex for use in a light portable back-rest such as would be attached to stretchers. U.S. Pat. No. 2,040,942 goes a long way in providing simplicity of LII construction but that patent shows only a pair of pins which must be individually manipulated in order to adjust the angle of the back member.

Particularly when the back-rest is to be used on stretchers it must be strong, reliable, easy to use and also desirably inexpensive. A particularly important feature for a stretcher back-rest is that it must have an extremely simple adjustment mechanism and preferably this should be operable by one hand so that an attendant can without any assistance adjust the position of a back-rest for a non-ambulatory patient. This means that there should be some kind of mechanism which will simultaneously release locking mechanisms on both sides of the back-rest and such a mechanism has never been provided in any of the light-weight type of back-rests such .as stretcher or patio chair back-rests. It is, therefore, the object of the present invention to provide an extremely simple yet reliable adjustable locking mechanism which can be manipulated with one hand by an attendant or even manipulated by a patient who is leaning against the back-fest.

SUMMARY OF THE INVENTION In accordance with this invention there is provided an adjustable back-rest which is particularly adapted for attachment to a stretcher, cot or bed. This back-rest comprises a substantial U-shaped tubular frame having a pair of side limb members joined by an upper cross bar. Each side limb member has at the lower end thereof a yoke member in the form of a pair of parallel, spaced ears with a slot therebetween. The ears are pivotally connected to a clamp member for connecting the back-rest to the stretcher, cot or bed and this clamp member has a projection extending into the slot. The projection has an arcuate face parallel to the pivot axis and this arcuate face has a series of spaced, radially extending holes. A locking pin is mounted in each yoke member and is spring-biased into engagement with one of the radial holes. The locking pins in the two yokes are connected together by an elongated flexible member which extends up through the side limbs and across between the side limbs with a portion thereof being exposed as a loop either above or below the cross bar. Thus, by simply pulling on this exposed loop, both of the pins are released from the holes and the back-rest can be adjusted to any desired position. When the back-rest has been moved to the desired position, the loop is released so that the pins can once again engage the pair of holes and the back-rest is fixed in the new angular position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The back-rest has a sheet or fabric back support exceeding across between the side limbs and this may also be attached to the cross bar. The elongated flexible member is preferably in the form of a nylon coated steel cable, e.g., airplane cables, and it preferably extends across between the side limbs behind the sheet or fabric in an upper region of the tubular frame. Alternatively, the cable can extend up into the cross bar, emerging through a pair of spaced holes to form an exposed loop adjacent the cross bar.

The clamp members can be of a permanently mounted type or they can be of an easily releasable type for a temporary back-rest. The releasable 'clamp member can conveniently be in the form of two semicylindrical portions hinged at one side. The opposite sides of each clamp member have a bolt extending between a pair of lugs and a wing nut whereby the clamps may simply be placed onto a tubular frame closed and tightened by means of the wing nut thereby securely mounting the back-rest on the bed arrangement.

While the back-rest of this invention is particularly adapted to be clamped onto a stretcher, cot or bed for temporary use, it can also be made as a permanent component during construction of the stretcher, cot or bed. Of course, in either permanent or releasable form it can also be used for other purposes such as lawn and patio chairs, lounges, etc.

Other features and advantages of the invention will appear from the following description, taken in connection with the drawings in which:

FIG. 1 is a view showing a side elevation of a stretcher with an adjustable back-rest of the invention attached;

FIG. 2 is an elevation of the back-rest itself;

FIG. 3 is a sectional view showing details of a connecting yoke;

FIG. 4 is a perspective view of a clamp member;

FIG. 5 is an end elevation of the clamp member, and

FIG. 6 is a side elevation of the clamp member.

As can be seen very simply from 'FIG. 1, the back-rest B is connected to side tubular frame members of a stretcher S by means of the novel pivot connectors P. As can better be seen from FIGS. 2 and 3 each backrest has a substantially U-shaped frame 10 with a pair of side limbs 10a joined by an upper cross bar 10b. The intermediate portion of the back-rest is covered by a sheet or woven fabric 11 which wraps around the side limbs 10a and cross bar 10b. Oblique portions of the fabric are cut away at the corners between side limbs 10a and cross bar 10b.

Connected to the lower ends of side limbs 10a are yoke members 12 and each yoke member has a projecting portionof reduced diameter 13 which fits snugly within a side limb member 10a. Each yoke also has a pair of parallel spaced cars 14 forming a slot 15 therebetween and a pivot hole 16 extends across through the cars 14. An axial hole 17 also extends into the upper shank of yoke 12 and this hole continues upwardly as a concentric hole of smaller diameter 21. Within the hole 17 is mounted a locking pin 18 which is spring biased downwardly by means of a small coil spring 19. Attached to the upper end of pin 18 is a shaft 20 which extends upwardly through hole 21 and is connected to a flexible plastic coated wire cable 22 by means of a connector member 23. .The cable 22 is connected to both locking pins 18 as shown in FIG. 2 with the cable 22 extending up the inner core of side limb members 10a through holes 24 and across between members 10a below cross bar 10b. Preferably the cut away portions of the fabric 1 I extend below the cable loop 22a so that the loop will be accessible from the front of the backrest.

By grasping and pulling on the loop 22a, it is possible to release both locking pins 12. This can be done either from behind the back-rest or by reaching through with fingers or thumbs from the front.

As will be seen from FIG. 1, the yokes 12 are connected to pivot members P and these are in the form of clamp members as illustrated in FIGS. 4 to 6. Each clamp member has an upper semi-cylindrical section 25 and a lower semi-cylindrical section 26. These are pivotally connected at one side by means of projecting lugs 27 and 28 and pivot pin 29. The opposite side of each clamp has a pair of upper projecting lugs 30 and a pair of lower-projecting lugs 31.'A bolt member 32 is pivotally mounted between the upper lugs 30 by means of pivot pin 33 and the lower end of this bolt 32 has threading 34. A wing nut 35 and washer 36 are mounted on the bolt.

Projecting upwardly from the upper portion of the upper semi-cylindrical member 25 is a pivot projection 37'having an arcuate face 38. Extending radially into this arcuate face are a series of spaced holes 39. Also extending across through the projection 37 parallel to face 38 is a hole 40. Finally there is provided an abutment member 41. While a 90 arcuate face is shown, it

will be appreciated that this is in no way limiting and the arcuate face can equally well extend through 80.

The yoke members are pivotally connected tothese projections 37 by means of a pivot pin extending through hole 16 of the ears l4 and hole 40 of the projection 37. The pins 18 engage the radial holes 39. An abutment 41 may be included to limit the distance of movement of the yoke member in one direction. However, it is generally preferred to have no such abutment so that the back-rest can swing fully in each direction.

When the back-rest is to be attached to a stretcher or similar device having a tubular frame, the clamp memher is simply opened as shown in FIG. 4 and the upper semi-cylindrical portion is rested on the tubular frame. The lower semi-cylindrical portion is then swung up against the lower half of the frame and the wing nut 35 and washer 36 are brought into engagement with the lugs 31. The wing nut is then tightened to firmly clamp the back-rest onto the stretcher in the manner shown in FIGS. 5 and 6.

With the back-rest firmly in place it will be seen that it provides a very simple and neat construction with an absolute minimum of exposed parts. The only exposed part which is in any way in evidence is the'short loop of cable 22a at the top of the back-rest. Moreover, this construction is not only extremely simple and inexpensive to manufacture but also provides the very important advantage that the locking pins on both sides of the back-rest can be easily released simultaneously merely by pulling on the loop 22a. This greatly simplifies mat ters for an attendant who is arranging the position of a non-ambulatory patient or, in the case of patients in better health, they can actually adjust the back-rest themselves merely by reaching up behind their head and pulling on the loop 220.

I claim:

1. An adjustable back-rest for a stretcher comprising a substantially U-shaped tubular frame having a pair of side limb members joined by an upper cross bar, each said side limb member having at the lower end thereof a yoke member in the form of a pair of parallel, spaced ears with a slot therebetween, said ears being pivotally connected to a clamp member for connecting the backrest to a stretcher, said clamp member having a projection extending into said slot, said projection having an arcuate face parallel to the pivot axis with said arcuate face having a series of spaced, radially extending holes, a locking pin mounted in each yoke member and being spring biased into engagement with one of said radial holes, said pins being connected together by a flexible cable member which extends up within said side limbs and across between said side limbs through holes in the tubular walls with a portion of the cable between the side limbs beingexposed as a loop, whereby both pins can be released from the holes to adjust the back-rest by pulling on said'loop.

2. A back-rest according to claim 1, wherein the cable emerges through holes in the side limbs and extends across-between the side limbs below the cross bar.

3. A back-rest according to claim 2, wherein a sheet or fabric extends across between the side limbs and around the cross bar, with the cable being positioned behind the sheet or fabric.

4. A back-rest according to claim 3, wherein portions of the sheet or fabric are cut away to expose the cable from the front of the back-rest.

5. A back-rest according to claim 1, wherein the cable is a plastic coated steel cable.

6. A back-rest according to claim 1, wherein the clamp member is of an easily releasable type for temporarily attaching the back-rest to a stretcher.

7. A back-rest according to claim 6, wherein the clamp member is'in the form of two semi-cylindrical portions hinged atone side and connected at the opposite side by means of a bolt and wing nut.

8. A back-rest according to claim 1, wherein the ar' cuate face extends through a arc. 

1. An adjustable back-rest for a stretcher comprising a substantially U-shaped tubular frame having a pair of side limb members joined by an upper cross bar, each said side limb member having at the lower end thereof a yoke member in the form of a pair of parallel, spaced ears with a slot therebetween, said ears being pivotally connected to a clamp member for connecting the back-rest to a stretcher, said clamp member having a projection extending into said slot, said projection having an arcuate face parallel to the pivot axis with said arcuate face having a series of spaced, radially extending holes, a locking pin mounted in each yoke member and being spring biased into engagement with one of said radial holes, said pins being connected together by a flexible cable member which extends up within said side limbs and across between said side limbs through holes in the tubular walls with a portion of the cable between the side limbs being exposed as a loop, whereby both pins can be released from the holes to adjust the back-rest by pulling on said loop.
 2. A back-rest according to claim 1, wherein the cable emerges through holes in the side limbs and extends across between the side limbs below the cross bar.
 3. A back-rest according to claim 2, wherein a sheet or fabric extends across between the side limbs and around the cross bar, with the cable being positioned behind the sheet or fabric.
 4. A back-rest according to claim 3, wherein portions of the sheet or fabric are cut away to expose the cable from the front of the back-rest.
 5. A back-rest according to claim 1, wherein the cable is a plastic coated steel cable.
 6. A back-rest according to claim 1, wherein the clamp member is of an easily releasable type for temporarily attaching the back-rest to a stretcher.
 7. A back-rest according to claim 6, wherein the clamp member is in the form of two semi-cylindrical portions hinged at one side and connected at the opposite side by means of a bolt and wing nut.
 8. A back-rest according to claim 1, wherein the arcuate face extends through a 90* arc. 